The following Stock/Super Stock horsepower changes were released July 9, 2013 produced by the Automatic Horsepower Factoring System (AHFS). This is the first of two scheduled horsepower adjustments for this year. All changes are effective July 9, 2013. It should be noted that these changes include only results produced by the AHFS, and do not include written letters or requests. Those changes are listed separately.

        The AHFS is a program based on actual run data compiled from all available runs at NHRA events. The data-based format provides the ability to calculate average performances for any class and/or engine combination in Stock and Super Stock. The trigger point for the system is 1.00-second or more under the respective index, and must be produced on two different occasions. Engine-combination averages and class averages are then computed and analyzed to determine if a change is warranted. The amount of change is calculated on a stepped percentage basis. Where applicable, adjustments will be effective for the specific car model or body style being evaluated. An automatic adjustment is instituted outside the two-time a year process when a 1.20 and under run is recorded during any NHRA event.

        Any comments, thoughts, or requests must be sent in writing to: National Hot Rod Association; Technical Department; attn: AHFS; P.O. Box 5555, Glendora, CA 91740; or e-mail, http://www.nhraracer.com/ahfs.asp or bbachelder@nhra.com.

                           Stock Horsepower Changes

Complete for 1st half rating period of 2013

Engine                 OEM         NHRA      New

Make          CID     HP            HP           HP           Years Affected

Buick           350      175-195    260          264          72-74 GS

Chev           427      425           435          445          12-13 COPO

Mopar          148      180           194          199          2004 PT Cruiser

Mopar          370      385           399          408          09-10 Drag Pak

Mopar          392      375           375          380          2010  Drag Pak

Ford            281      235           266          272          2010  Cobra Jet

Ford            281      235           257          263          2010  Cobra Jet

Ford            302      500           507          519          2013  Cobra Jet

Ford            330      425           493          505          2008  Cobra Jet

Ford            352      285           312          316          2010  Cobra Jet

GM              207      170           170          173          99-05 Grand Am

GM              350      170           254          258          79-80 Cutlass

                      Super Stock Horsepower Changes

Complete for 1st half rating period of 2013

Engine                 OEM          NHRA     

Make          CID     HP            HP           New HP  Years Affected

Cadi            350      180           229          232          1977  GT

Chev           396      425           405          411          1965  Corvette

Chev           427      430           476          482          68-69 Corvette

Chev           427      430           489          496          1969  Corvette

Ford            302      500           500          512          2013  Cobra Jet

Ford            330      450           450          456          2012  Cobra Jet

Super Stock Index Changes

Class          Old Index            New Index

SS/ES             12.25                12.20

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